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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    
</head>
<body>
    <div id = "box">123</div>
    <h2 class="bigChina">中国</h2>
    <h3>台湾</h3>
    <h3 class="smallDog">小日本</h3>


    <script>
        //获取div对象
        const boxObject = document.querySelector("#box");
        const bigChina = document.querySelector(".bigChina");
        const smallDog= document.querySelector(".smallDog");


        console.log(boxObject);
        console.log(bigChina);
        console.log(smallDog);


        bigChina.innerHTML="中国即将举办9.3大阅兵";
        
        smallDog.innerHTML = "小日本，狗改不了吃屎"



    </script>
</body>
</html>